Federal drug enforcement agents swarmed DL Labs on Kent Street on Wednesday, claiming that the lab is part of an underground quaalude trafficking pipeline that stretched all the way to California.

The raid was part of “Operation Lude Behavior,” a three-year investigation into the alleged $3.5-million illegal drug network. The lab was a pivotal meeting point, prosecutors said.

“Thousands” of pills were reportedly seized, but it was unclear if any of the 1970s drug of choice was actually found.

Federal prosecutors alleged that would-be quaalude king Dennis Patrick Fairley, a West Coast chemist, manufactured the pills at a lab in California — interestingly enough, the same lab that recently merged with DL Labs.

Farley then sold the drugs directly to suspects Frank Bisman, Jason Abbate and Neil Weinstock, who distributed them throughout the city.

Bisman and Abbate allegedly met with Fairley on a monthly basis at DL Labs, a place identified by investigators as “the Brooklyn lab.”

Bisman and his team reportedly bought the ’ludes for $7 a pill and sold them for $11, according to intercepted phone conservations. More than 100,000 quaaludes were bought and sold between 2008 and 2010, officials estimate.

But DL Labs claims that it is not in the quaalude business. Its Web site claims that the chemical plant conducts independent tests on chalks, coatings and sealants.

Despite the arrests, federal drug busters said quaalude use isn’t suddenly surging in Brooklyn. To paraphrase L.L. Cool J, you can’t call it a comeback — quaaludes have been here for years.

“Obviously, quaaludes have not been completely eradicated. They’re still out there,” said Donald Cateano, a spokesman for the federal Drug Enforcement Agency, adding that many of the suspects arrested were well over 50. They may have been popping the “old school” pills out of a sense of nostalgia. “[The bust] doesn’t indicate that there is more or less of a market for them. It’s a recurring problem.”

Still, he said his agents “were hard pressed to remember the last time they handled a quaalude case.”